A new species of the xenodermid snake genus Achalinus Peters, 1869 is described from Fujian Province, China, based on six specimens. Bayesian inference and maximum likelihood analyses based on a mitochondrial DNA fragment (CO1) indicated the new taxon is different from its congeners (p–distance ≥ 18.5%). Morphologically, the new species can be diagnosed from the other species by a combination of following characters: (1) dorsal scales 23 rows throughout, strongly keeled, the most outer rows on both sides also keeled and slightly enlarged; (2) tail relatively longer, TaL/TL ratio 0.26–0.29 in males, 0.21–0.22 in females; (3) maxillary teeth 30–33; (4) length of suture between internasals significantly longer than that between prefrontals; (5) nasal divided into two sections by nasal cleft; (6) a single loreal; (7) SPO 1, seldom 2; (8) SPL 6, the fourth and fifth contacting eye; (9) IFL5, rarely 6, the first three touching the first pair of chin shields; (10) TMP 7–9, arranged in three rows; (11) VS 142–149 in males, VS 152–154 in females; (12) SC 74–81 in males, SC 63–65 in females, arranged in a single row; (13) cloacal entire; (14) greyish brown above, pale yellow beneath; (15) dorsum with an indistinct longitudinal vertebral stripe. The description of the new species brings the total species of Achalinus to 19.

The interactions between hosts and the gut microbiota are intricate and can significantly affect the ecology and evolution of both parties. Various host traits, including taxonomy, diet, social behaviour, and external factors such as prey availability and the local environment, all play an important role in shaping composition and diversity of the gut microbiogta. In this study, we explored the impact of intestinal microorganisms on the host in adapting to their respective ecological niches in two species of snakes. We collected feces from Lycodon rufozonatus and Lycodon rosozonatus from different geographical locations and used 16S rRNA gene sequencing technology to sequence the v3‐v4 region. The results revealed that there was no significant difference in the alpha diversity of intestinal microorganisms between L. rufozonatus and L. rosozonatus. The gut microbiota of all individuals comprised four main phyla: Pseudomonadota, Bacteroidota, Bacillota, and Actinomycetota. At the genus level, the genus Salmonella dominated the enterobacterial microbiota in the samples from Hainan, while there was no obvious dominant genus in the enterobacterial microbiota of the samples from the other four localities. Comparative analysis of enzyme families annotated to the gut microbiota between L. rufozonatus and L. rosozonatus from the four sampling regions by CAZy carbohydrate annotation revealed that nine enzyme families differed significantly in terms of glycoside hydrolases (GHs). In addition, we compared the composition of gut microbial communities between L. rufozonatus and L. rosozonatus and investigated the impact of the differences on their functions. Our results will provide insights into the coevolution of host and gut microbes.

Gloydius shedaoensis is an insular and vulnerable pitviper that is endemic to Snake Island, northeastern China. In this study, we successfully sequenced mitochondrial genomes of two individuals of G. shedaoensis. The complete mitochondrial genomes of G. shedaoensis are circular molecular with 17 222 and 17 221 bp in length respectively, which both contain 2 ribosomal RNA (rRNA) genes, 13 protein-coding genes, 22 transfer RNA (tRNA) genes, an origin of light-strand replication (OL) and two non-coding control regions. Compared with previously published mitochondrial genomes of Gloydius species, the base composition and gene arrangement are rather conservative. A Bayesian phylogenetic tree using the complete mitochondrial genomes of all viper species available showed a consistent result with previous studies.

Indotyphlops braminus, the only known triploid parthenogenetic snake, is a compelling species for revealing the mechanism of polyploid emergence in vertebrates. In this study, we applied PacBio isoform sequencing technology to generate the first full-length transcriptome of I. braminus, aiming to improve the understanding of the molecular characteristics of this species. A total of 51,849 nonredundant full-length transcript assemblies (with an N50 length of 2980 bp) from I. braminus were generated and fully annotated using various gene function databases. Our analysis provides preliminary evidence supporting a recent genome duplication event in I. braminus. Phylogenetic analysis indicated that the divergence of I. braminus subgenomes occurred approximately 11.5 ~ 15 million years ago (Mya). The full-length transcript resource generated as part of this research will facilitate transcriptome analysis and genomic evolution studies in the future.

Sexual dimorphism and geographic variation are common in snakes. The white-lipped pitviper (Trimeresurus albolabris) is a common and widely distributed venomous snake species throughout the Southeast Asia. We report on the sexual dimorphism and geographic variation of T. albolabris in China. Ninety-nine specimens (57 females and 42 males) were examined by using analysis of variance, analysis of covariance, principal component analysis, and other statistical methods for 68 morphological characters. The result showed that T. albolabris displays significant sexual dimorphism in several external characters. Females have a longer snout-vent length, wider anal scales, and larger head size than males, whilst males exhibit a longer tail length and larger number of subcaudal scales. No significant geographic variation was detected, suggesting the absence of obvious morphological differentiation among local populations in China.